Datasheet

INSYS Modem 336/56k 4.1 (UL) Functions
5.4.1 V.42bis data compression
AT%C3
AT%C0
Switch on V.42bis data compression.
Switch off V.42bis data compression
AT%C2
AT%C3
V.42bis data compression may only be performed for a V.42
connection (LAP-M or MNP 4). First of all, V.42bis generates a
so-called dictionary for the data compression, which contains
frequently used character sequences. After that, only short
references to these character sequences and not the complete
character sequences are transmitted to the other modem.
V.42bis cannot re-pack packed data.
5.4.2 MNP 5 data compression
The modem masters the Microcom Networking Protocol Level
5. MNP 5 data compression can only be performed for an er-
ror corrected MNP 4 connection. MNP 5 replaces frequently
used characters by shorter characters, so-called tokens.
MNP 5 cannot re-pack packed data.
AT%C1
AT%C3
5.4.3 V.44 data compression
The V44 data compression offers better compression of typi-
cal internet content than V.42bis. V.44 also requires an error
corrected connected, just as V.42bis, and cannot re-compress
already compressed data.
Switch off V.44 data compression:
Switch on V.44 data compression:
AT+DS44=3
AT+DS44
=
0
July 06 25